Lisa Gerritsen (born Lisa Orszag; December 21, 1957)^[1] is an American former child actress. She is most famous for her role as Bess, the independent-minded daughter of Phyllis Lindstrom on the 1970s television series The Mary Tyler Moore Show and its spin-off Phyllis.

Lisa Gerritsen was born Lisa Orszag in Los Angeles and is the granddaughter of child actor and screenwriter True Eames Boardman, and the great-granddaughter of silent film actors True Boardman and Virginia True Boardman. Her acting career began when she was eight years old.^[2] Encouraged by her mother and grandfather, she landed her first professional role in an episode of The Doris Day Show in 1968.

After The Doris Day Show, Gerritsen had guest-star or cameo appearances in several television shows, including The Odd Couple, Bonanza, The Courtship of Eddie's Father, The Virginian, and Family Affair.^[3]

Gerritsen appeared in several episodes of Gunsmoke, which helped to land her first regular role as Lydia Monroe, the precocious daughter of William Windom's character, John Monroe, a Thurber-like writer and cartoonist, in the 1969 NBC comedy series My World and Welcome to It. Also starring Joan Hotchkis as Ellen, Lydia's mother, the somewhat dark situation comedy was based on the cartoons and comedy of author James Thurber, combining live-action storylines of family strife and social satire with animated cartoon characters that broke into the frame during segments featuring Monroe's daydreams and fantasies. Despite having won two Emmy awards,^[4] the show was cancelled after only one season.

In 1970, Gerritsen (credited as Lisa True Gerritsen) appeared as Hannah Carson on the TV western The Men From Shiloh (the rebranded name for The Virginian) in the episode "Hannah". Also that year, Gerritsen was cast as Bess Lindstrom, the quick-witted daughter of landlord Phyllis Lindstrom (Cloris Leachman), a mother who believed in progressive parenting, on The Mary Tyler Moore Show. Bess was a recurring character throughout the length of the series and Gerritsen continued playing the role in the spinoff, Phyllis.

In addition to television, Gerritsen performed in several movies. She made her first big-screen appearance in Airport, playing the role of Libby Bakersfeld. She also appeared as Linda in The War Between Men and Women, starring Jack Lemmon and Barbara Harris.

She left acting at the age of 20, shortly after the show Phyllis was cancelled.